Process for improving a hydrocarbon charge stock by contacting the charge with water at elevated temperature and pressure

ABSTRACT

OIL REFINING IS EFFECTED BY HEATING UNDER AGITATED FLOW CONDITIONS CRUDE OIL OR RESIDUAL OIL WITH WATER AT A TEMPERATURE SUFFICIENT TO FORM A FOAM WHICH IS COOLED BELOW THE VAPORIZATION TEMPERATURE OF WATER TO FORM A STABLE EMULSION CONTAINING SULFUR, CARBON RESIDUES, ASPHALTENES, NICKEL AND VANADIUM. AFTER REMOVAL OF THE EMULSION, THE OIL CAN BE A FUEL OR A CATALYTIC PROCESSES.

Apnl 3, 1973 R. F. WILSON ET AL 3,725,250

PROCESS FOR IMPROVING A HYDROCARBON CHARGE STOCK BY CONTACTING THE CHARGE WITH WATER AT ELEVATED TEMPERATURE AND PRESSURE Filed Jan. 22, 1971.

FEED 1 WATE R 2 1 FILTER\ HEATE R i La ALSTRIPPER SEPARATOR IUI \ FLUID CATALYTIC CRACKER United States Patent O 3,725,250 PROCESS FOR IMPROVING A HYDROCARBON CHARGE STOCK BY CONTACTING THE CHARGE WITH WATER AT ELEVATED TEM- PERATURE AND PRESSURE Raymond F. Wilson and Reese A. Peek, Fishkill, Norman D. Carter, Poughkeepsie, Edward L. Cole, Fishkill, and

Howard V. Hess, Glenham, N.Y., assignors to Texaco Inc., New York, N.Y.

Continuation-in-part of application Ser. No. 20,285, Mar. 17, 1970. This application Jan. 22, 1971, Ser. No. 108,859

Int. Cl. Cg 17/08 US. Cl. 208-208 R 10 Claims ABSTRACT OF THE DISCLOSURE Oil refining is effected by heating under agitated flow conditions crude oil or residual oil with water at a temperature sufficient to form a foam which is cooled below the vaporization temperature of water to form a stable emulsion containing sulfur, carbon residues, asphaltenes, nickel and vanadium. After removal of the emulsion, the oil can be used as a fuel or in catalytic processes.

CROSS-REFERENCE TO CO-PENDING APPLICATION This application is a continuation-in-part of Ser. No. 20,285, filed Mar. 17, 1970, now abandoned.

BACKGROUND OF THE INVENTION This invention relates to a process for upgrading crude or residual oils by the removal of certain contaminants as well as to the use of such upgraded oils in a cracking process for the production of high quality hydrocarbons.

Heavy hydrocarbon fractions contain a considerable quantity of contaminating components such as asphaltenes, trace metals, carbon residues as well as sulfurous compounds. The presence of such contaminants renders these oils unsatisfactory for inclusion in boiler fuels, turbine fuels and the like because of the odor emissions, gum and varnish formation they occasion. Where these oils are to be subjected to further refining operations where catalysts are employed, the presence of sulfur, of asphaltenic materials which are coke precursors, and of organometallic compounds rapidly deactivates most catalysts. It is, therefore, very desirable to remove these contaminants from an oil before refining.

Heretofore several processes have been suggested and tried in an attempt to remove such contaminants including liquid-phase hydrogenation, vapor phase cracking and plural stage hydro-refining-a combination of noncatalytic pretreatment and catalytic hydro-refining. Regardless of their respective merits and limitations, all these processes are characterized by an undesirable featurethe use of large quantities of hydrogen.

The main object of the present invention is to provide means for converting large quantities of poor quality stock without the use of expensive solvents or of hydrogen.

An equally important object of the invention is the utilization in a catalytic cracking process of an oil converted as indicated in the above manner so as to produce higher liquid yields at lower coke yields.

SUMMARY OF THE INVENTION In accordance with this invention, residual oils, whole crudes, gas oils, cycle oils and coker 0118 containing con- 3,725,250 Patented Apr. 3, 1973 ice DETAILED DESCRIPTION OF THE INVENTION The invention can best been described by reference to the accompanying drawing, which is a flow sheet illustrating one embodiment of the invention. Referring to the figure, an oil of the type above described and containing carbon residue, sulfur, asphalten-es and trace metals is fed through line 1 to a heated reaction coil 3 and mixed with the water supplied through line 2. The oil and water mixture are raised to a temperature in the heated reaction coil sufiicient to form a foam or disperse system which consists of water vapor (steam) being the disperse phase and the oil being the dispersion medium. Flow through the coil provides agitation to the mixture. Additionally the temperature in the reaction coil must be sufficient such that when the foam or disperse system is cooled below the vaporization temperature of water a stable emulsion is formed with the contaminants hereinbefore mentioned. As shown, the efiluent from the reaction coil flows to a gas-liquid separator 4 where it is cooled to condense the water vapor and to form the stable emulsion. The light hydrocarbon gases formed in the reaction coil are removed from the gas-liquid separator through line 5. The liquid phase remaining comprises a stable emulsion dispersed in the treated oil. The liquids then pass through line 6 into filter 7 where the stable emulsion containing the contaminants is withdrawn through line 8. The emulsion may be further processed in known manner so as to recover valuable metals such as nickel and vanadium which may be present therein.

Through line 9, the material goes to stripper 10 where water is removed through line 11. The decontaminated oil which now has a higher API gravity is withdrawn through line 12. It is important to note that at this point the oil is pure enough to be used as fuel or the like; but it may be further processed. In the embodiment shown in the flow sheet, the oil is sent onto a fluid catalytic cracking unit 13 containing cracking catalysts and the products are withdrawn through line 14.

The general and preferred operating conditions for the disclosed process are listed below. It is noteworthy to remark that the optimum treating temperatures and amounts of water needed to form a stable emulsion will vary within the limits set forth for various types of charge oils.

General Preferred Operating condition range range Pretreat:

Temperature, F 600-900 Pressure, p.s.i.g 0-200 Gas rate, s.c.f.b 0 Oil LHSV (basis reactor olum 2-5. 0 5-3.0 Water L HSV (basis reactor volume) 1-5. 0 2-3. 0 Separating temperature, F 50-210 -200 Separating pressure, p.s.l.g 0-600 0-200 Cracking:

Temperature, F 800-1, 840-1, 000 Catalyst contact time, sec 2-600 5-300 Space velocity, basis total teed w./hr./'w. 3-1, 800 1. 0-700 Reactor pressure, p.s.i 0-200 0-50 Recycle as percent FF O-100 0-70 Per pass conversion, vol. percent 30-80 40-75 Ultimate conversion vol. percent 30-100 50-85 The following examples illustrate but do not limit the invention.

Example I In the series of tests constituting this example an oil containing a large amount of sulfur, carbon residue, and asphaltenes and a small amount of trace metals is mixed with water vapor (steam) to form a dispersed system and treated under the conditions shown.

The reaction vessel used in these tests is a 1 /2 inch I.D. reactor packed with Berl saddles. The dispersed system consisting of water vapor in oil is withdrawn from the reaction vessel at the treating temperature, cooled to about 150 F. to form a stable emulsion containing the contaminants dispersed in the treated oil, and the stable emulsion is separated from the treated oil at about 150 F. by filtration.

Table I lists tests performed on the contaminant-com taining oils used in this and the following example. Table II lists operating data and product quality tests noted when applying this process for the removal of contaminants from Arabian Atmospheric Reduced Crude. It will be noted from the data in Table II that the present process can be employed at 800 F. to remove a large portion of the contaminants present in the oil and to convert an appreciable portion of the 850 F. material. However, it will also be noted that when processing the oil at lower temperatures (600 and 700 F.) a stable emulsion does not form.

Example II In the series of tests constituting this example, an oil containing a large amount of nickel and vanadium as Well as moderate amounts of sulfur, carbon residue, and asphaltenes was treated in the presence of water under the conditions of Example I.

Table III lists operating data and product quality tests when applying this process for the removal of contaminants from Lago Medio Atmospheric Reduced Crude. It will be noted that the process of this disclosure may be employed to remove a large portion of the trace metals present in the oil. It will also be noted that the amount of the stable emulsion which forms increases with temperatures and that the removal of contaminants from the charge oil does not occur at 600 and 700 F. even though an emulsion formed. Only at 800 F. was there a reduction in the metals and carbon residue content as shown by the product oil tests.

Example III In another test, Lago Medio Atmospheric Reduced Crude was treated in a manner used in Examples I and II except that no water was admixed with nor included in the feedstock. Data for this test are given in Table IV.

It will be noted that no filterable material was obtained in this test and the product oil had an increased carbon residue and asphaltene content over that present in the charge oil.

TABLE I.-CHARGE STOCK QUALITY Charge stock name TABLE II.-TESTS FOR ARABIAN ATMOSPHERIC REDUCED CRUDE Test Operating conditions:

Temperature, F 600 700 800 Pressure, p.s.i.g 0 0 0 Treated liquid, wt. percent 100 100 94. 7 Stable emulsion (dried), wt. percent None None 5. 3 Product quality-treated oil:

Vac. dist. wt. percentHzO 7.3 0 7 1B 0 F 15. 8 7. 3 13. 5 38. 2 33. 4 42. 5 38. 7 59. 3 43. 3 1. 8 2. 44 1. 5. 4 8. 6 6.00 Asphaltenes, wt. percent 2. 7 3. 2. 44 Nickel, p.p.m 10 Vanadium, p.p.m 10 Stable emulsion (dried 4. 60 32.1 30. 7 55 Vanadium, p.p. 146

TABLE III.TESTS WITH LAGO MEDIO ATMOSPHERIC REDUCED CRUDE Test Operating conditions:

Temperature, F 600 700 800 Pressure, p.s.i.g 0 0 0 LHSV basis reactor Vol.2

Oil 1. 0 1. 0 1. 0

33 33 33 Gas rate, s.c.f.b 0 0 0 Yields basis oil charge:

Treated oil, wt. percent 98. 0 95. 38 92. Stable emulsion (dried), wt. percent 2. 0 4. 72 7. 05 Product qualityTreated oil:

Vac. dist., wt. percent-Hz0 .9 7. 6 1. 9 IBP050 F 10. 88 17. 0 16. 7 050-850 F 34. 5 27. 2 34. 9 850 F.EI 53. 8 50. 0 46. 5

Sulfur, wt. percent 1. 92 1. 72 1.80

Carbon residue, wt. percent. 7. 11 6. 84 5. 12

Asphaltenes, wt. percent. 2. 60 1. 90 3. 04

Nickel, p.p.m 20 19 10 Vanadium, p.p.rn 220 215 Stable emulsion (dried):

Sulfur, wt. percent 2. 12 2. 0 1. 97

Carbon residue, wt. percent;

Asphaltenes, wt. percent- Nickel, p.p.m 20 19 52 Vanadium, p.p.m 220 215 606 TABLE IV.-TEST EMPLOYI-NG NO WATER IN TREAT WITH LAGO MEDIO RED CRUDE Test A Operating conditions:

Temperature, F. 750 Pressure, p.s.i.g 0 LHSV basis reactor Vol.1

Oil 1.0

Water 0 Gas rate, s.c.f.b. 0 Yields basis oil charge:

Treated oil, wt. percent 100.0 Stable emulsion, wt. percent None Product quality: treated oil:

Gravity, API Vac. dist. wt. percent:

IBP-650 F. 14.3 650850 F 27.7 850-EP 58.0 Sulfur, wt. percent 2.0 Carbon residue, wt. percent 6.86 Asphaltenes, wt. percent 3.70 Nickel, p.p.m. 21 Vanadium, p.p.m. u fi.., 220

Example IV In this example an oil containing a large amount of sulfur, carbon residue, asphaltenes and trace metals was treated in the presence of water under the conditions of Ex. I. The reaction vessel used in this test was a 1 /2 inch I.D. reactor packed with Berl saddles. The treated oil and stable emulsion were withdrawn as a suspension and separated by filtration.

The treated oil was then charged in three separate and equal portions of 0.8 gram each over 2.5 grams of Davison XZ 25 plus cracking catalyst. The catalyst was calcined for 6 hrs. in a muflle furnace at 1000" F. prior to being placed in the Vycor reactor. A /z inch layer of mullite chips were placed in the reactor to act as a preheater. The catalyst was then calcined for 1% hours at 1000 F. using 25 ml./min. of helium to purge. The temperature was then reduced to 900 F. and the helium flow adjusted to 15 ml./min. Each hydrocarbon sample was injected into the reactor /2 inch above the mullite chips within l00160 sec. The helium flush was then continued for 30 minutes.

The liquid product was collected from each separate run in a 10 cc. vial at 32 F. and the gas was collected in plastic bags. The liquid samples were weighed and analyzedby gas chromatography for peaks up to C The gas samples, (3,; to C were also analyzed by gas chromatography and the weight of hydrocarbon in the gas was calculated from peak height and gas volume.

Example V In this example a sample of raw Arabian Atmospheric Reduced Crude was catalytically cracked without pretreatment. The cracking was carried out in the same way as described in Example IV.

The results of the cracking evaluation are shown in Table VI. The evaluation showed! that the weight of gas produced decreased in each run and the weight of liquid increased. This indicates that the cracking catalyst was being rapidly deactivated during the evaluation. All of the liquid products boiled below C (550 F. at 15 mm. Hg) but in the third evaluation less than weight percent of the liquid product boiled below C (400 F.). The spent catalyst had a carbon content of 14.3 weight percent.

These above results when compared to the results obtained in Example IV show that the pretreated oil does not cause appreciable catalyst deactivation while the untreated raw oil will cause serious catalyst deactivation.

Example VI In this example Arabian Heavy Vacuum Gas Oil and a furfural extract from Arabian Heavy Cycle Gas were treated in the presence of water to remove carbon residue and trace metals. Both of these stocks were treated at the same conditions as the Arabian Atmospheric Reduced Crude was in Example IV. The results of these evaluations are shown in Table VII and indicated that these stocks when treated with water at high temperatures followed by removal of the stable emulsion would be more suitable for catalytic cracking than the raw stocks were.

TABLE V.P RETREATMENT AND CATALYTIC CRACKING OF ARABIAN ATMOSPHERIC REDUCED CRUDE Evaluation H: 0 treatment Catalyst cracking Charge 800 F. 900 F. 900 F. 900 F Pressure .s.l. 0 0 LHSV: p g 0 0 Oil 1. 0 33 33 .33

Water. 83 0 0 0 Gas rate, 0 15 15 15 Gas None Helium Catalyst- None Davison XZ-25 Plus Yields basis oil charge:

Liquid, wt. percent 94. 7 21. 2 62. 5 c5. 0

Gas, wt. percent 1 23. 8 22. 5 23. 8

Solids 5.3

Carbon on spent catalyst, wt. percent Product quality-Oil Vacuum dist, wt. percent 850 F. Sulfur, wt. percent Carbon residue, wt. percent Asphaltenes, wt. percent Nickle p.p.m

Vana 'um, p GO analysis,

Product quality-Solid:

Sulfur, wt. percent Carbon residue, wt. percent e1, p.p.m Vanadium, p.p.m

The results of both the pretreatment and cracking are shown in Table V. It can be seen that the pretreatment removed a large portion of the carbon residue, sulfur and trace metals present in the Arabian Atmospheric Reduced Crude charge. Also a significant amount of conversion of the 850 F. plus fraction was obtained during the thermal pretreat. The contaminants removed from the charge were collected in the stable emulsion separated from the treated oil by filtration.

In the catalytic cracking evaluation, the same weight of gas was produced in each run while the liquid production was nearly constant during the last 2 evaluations. In all runs the total liquid product boiled below C (550 F. at 15 mm. of Hg) and at least 50 weight percent boiled below C (400 F.) The spent catalyst had a carbon content of 10.7 weight percent.

.p.m., wt. percent.- boiling below 400 F Wt. percent boiling below 550 F. (at 15 mm. Hg)

TABLE VI.-CATALYTIC CRACKING OF ARABIAN ATMOSPHERIC REDUCED CRUDE Evaluationcatalyst cracking Temperature, F 900 900 900 Pressure, p.s.i 0 0 LHSV: g 0

i1 33 .33 33 Water 0 O 0 Gas rate, mL/min Gas. Helium Catalyst Davison XZ-25 Plus Yields basis oil charge:

Liquid, wt. percent 25. 0 51. 2 70. 0 Gas, wt. percent- 22. 5 18. 7 8. 7 Carbon on spent catalyst, wt. pereent.;.. 14. 3 Product quality-Oil GO analysis:

Wt. percent boiling below 400 F 51 45 Wt. percent boiling below 550 F. (at 15 mm.

TABLE VII.PRETREATMENT OF ARABIAN HEAVY VAC:

UUM GAS OIL AND FURFURAL EXTRACT FROM ARABI AN VACUUM GAS OIL Evaluation H20 H20 treatment treatment Charge Charge Arabian Arabian Heavy Furfural Gas Oil Extract Charge. 800 F Charge 800 F.

Pressure, p.s.l.g 0 LHSV:

Oil 1. 0 Water .33 Gas rate, m 0 Gas None Catalyst None Yields basis oil chg:

Liquid, wt. percent 98. 2 Gas, wt. percent- 1 Solid, wt. percent 1 8 Product quality-oil vacuum dist., wt. percent:

IBP-40 0 0 0 0 400-650 F 0 0 17. 4 26. 2 650850 F 12.4 39. 4 45. 4 51. 2 850 F. 87. 6 60. 0 37. 2 22. 6 Sulfur, wt. percen 2. 7 2. 6 4. 00 3. 00 Carbon residue, wt. percent. 1. 29 76 5. 33 4. 26 Asphaltenes, wt. percent. 1g 07g N rw- 5 5 5 In considering the disclosed process, it will occur to those skilled in the art that the stable water emulsion may be separated from the treated oil by sedimentation or by centrifuging instead of by filtration.

The foregoing examples and specification clearly indicate the advantages afforded by the process of the invention. Some of these advantages are:

It provides a method of separating sulfur, carbon residue, asphaltenes, and trace metals from an oil. It converts oils of low quality to useful stocks for inclusion in boiler fuels, turbine fuels, and charge stock for further refining. The valuable trace metals contained in many oils may be removed in the form of a stable emulsion that forms a solid residue when dried. This residue may be further processed to recover the valuable metal contained therein. The process does not require either expensive solvents or hydrogen to remove the contaminants from the oils.

What is claimed is:

1. A process for improving the quality of crude oil or residual oil containing sulfur, carbon residues, asphaltenic material and trace metal contaminants, comprising: heating said charge stock under agitated flow conditions with from about 5% to about 100% by weight of water based on the weight of said stock at a temperature ranging from about 500 to about 1000 F. at a pressure ranging from about 0 to about 600 p.s.i.g. to form a disperse system consisting of water vapor as the disperse phase and said stock as the dispersion medium; cooling said system to about 100 to 210 F. at a pressure of about 0 to 600 p.s.i.g. to form a stable emulsion with said contaminants; removing light hydrocarbon gases formed at said temperature and separating said contaminants-containing emulsion from said stock, said stock now having a higher API gravity and being substantially free of said contaminants.

2. The process according to claim 1, wherein said charge stock is heated to a temperature of between about 600 and 900 F. under a pressure of between about 0 and 200 p.s.i.g. and the disperse system thus formed is cooled to about 100 to 200 F. under a pressure of between 0 and 50 p.s.i.g.

3. The process according to claim 1, wherein the treated stock is stripped of water and catalytically cracked over a a cracking catalyst to produce distillate products.

4. The process according to claim 3, wherein said oil is catalytically cracked at a temperature ranging from about 800 to 1150 F. for a catalyst cracking time ranging from about 0.3 to 1800 p.s.i.g.

5. The process according to claim 1, wherein the treated stock is catalytically cracked at a temperature ranging between about 840 and 1000 F. for a catalyst contact time ranging from 0.5 to 300 seconds.

6. The process according to claim 1, wherein said stable emulsion is separated from said stock by filtration.

7. The process according to claim 1, wherein said emulsion is separated from said stock by centrifuging.

8. The process according to claim 1, wherein said emulsion is separated from said stock by sedimentation.

9. The process according to claim 1, wherin said hydrocarbon charge stock is selected from the group of residual oils, whole crudes, gas oils, cycle oils and coker oils.

10. The process according to claim 3, wherein said cracking catalyst is silica-alumina or a synthetic silicaalumina zeolite.

References Cited UNITED STATES PATENTS 2,402,799 6/ 1946 Arnold et al. 208208 R 1,862,942 6/1932 Ryan 208208 R 2,789,083 4/ 1957 Hardy 20825 1 2,825,678 3/1958 Jahnig 20888 1,957,787 5/1934 Krauch et al. 20888 2,728,714 12/1955 Winkler et a1 208251 DELBERT E. GANTZ, Primary Examiner J. M. NELSON, Assistant Examiner US. Cl. X.R. 208 

